day5, example

day5/dayFive.go

@@ -0,0 +1,113 @@
+package day5
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Almanach struct {
+	SeedToSoil,
+	SoilToFert,
+	FertToWater,
+	WaterToLight,
+	LightToTemp,
+	TempToHum,
+	HumToLocation map[int]int
+}
+
+func applyMap(source int, mapping map[int]int) int {
+	var result int
+	result, found := mapping[source]
+	if !found {
+		result = source
+	}
+	return result
+}
+
+func (a Almanach)locationForSeed(seed int) int {
+	soil := applyMap(seed, a.SeedToSoil)
+	fert := applyMap(soil, a.SoilToFert)
+	water := applyMap(fert, a.FertToWater)
+	light := applyMap(water, a.WaterToLight)
+	temp := applyMap(light, a.LightToTemp)
+	hum := applyMap(temp, a.TempToHum)
+	location := applyMap(hum, a.HumToLocation)
+	return location
+}
+
+func Run() int {
+	fmt.Println("the day 5")
+	inputDir := "day5/example"
+	seedToSoil := fmt.Sprint(inputDir, "/seed-to-soil")
+	soilToFert := fmt.Sprint(inputDir, "/soil-to-fertilizer")
+	fertToWater := fmt.Sprint(inputDir, "/fertilizer-to-water")
+	waterToLight := fmt.Sprint(inputDir, "/water-to-light")
+	lightToTemp := fmt.Sprint(inputDir, "/light-to-temperature")
+	tempToHum := fmt.Sprint(inputDir, "/temperature-to-humidity")
+	humToLocation := fmt.Sprint(inputDir, "/humidity-to-location")
+
+	seedsFileName := fmt.Sprint(inputDir, "/seeds")
+	seedsBytes, err := os.ReadFile(seedsFileName)
+	if err != nil {
+		panic(fmt.Sprint("error reading seeds file ", seedsFileName))
+	}
+	seedsLine := string(seedsBytes)
+	var seeds []int
+	for _, seedStr := range strings.Fields(seedsLine) {
+		seed, err := strconv.Atoi(seedStr)
+		if err != nil {
+			panic(fmt.Sprint("can't read seeds ", seedStr))
+		}
+		seeds = append(seeds, seed)
+	}
+
+	almanach := Almanach{
+		SeedToSoil: ReadMap(seedToSoil),
+		SoilToFert: ReadMap(soilToFert),
+		FertToWater: ReadMap(fertToWater),
+		WaterToLight: ReadMap(waterToLight),
+		LightToTemp: ReadMap(lightToTemp),
+		TempToHum: ReadMap(tempToHum),
+		HumToLocation: ReadMap(humToLocation),
+	}
+
+	result := math.MaxInt
+	for _, seed := range seeds {
+		location := almanach.locationForSeed(seed)
+		if location < result {
+			result = location
+		}
+	}
+
+	return result
+}
+
+func ReadMap(filename string) map[int]int {
+	result := make(map[int]int)
+	bytes, err := os.ReadFile(filename)
+	if err != nil {
+		panic(fmt.Sprintf("error reading file %s", filename))
+	}
+	text := string(bytes)
+	text = strings.TrimSpace(text)
+	for _, line := range strings.Split(text, "\n") {
+		nums := strings.Fields(line)
+		if len(nums) != 3 {
+			panic(fmt.Sprint("error, map line doesn't have 3 nums: ", line, nums))
+		}
+		destinaitonStart, err1 := strconv.Atoi(nums[0])
+		sourceStart, err2 := strconv.Atoi(nums[1])
+		rangeLength, err3 := strconv.Atoi(nums[2])
+		if err1 != nil || err2 != nil || err3 != nil {
+			panic(fmt.Sprint("error converting one of the numbers: ", nums))
+		}
+		for i := 0; i < rangeLength; i++ {
+			result[sourceStart+i] = destinaitonStart + i
+		}
+	}
+
+	return result
+}

day5/example/fertilizer-to-water

@@ -0,0 +1,4 @@
+49 53 8
+0 11 42
+42 0 7
+57 7 4

day5/example/humidity-to-location

@@ -0,0 +1,2 @@
+60 56 37
+56 93 4

day5/example/light-to-temperature

@@ -0,0 +1,3 @@
+45 77 23
+81 45 19
+68 64 13

day5/example/seed-to-soil

@@ -0,0 +1,2 @@
+50 98 2
+52 50 48

day5/example/seeds

@@ -0,0 +1 @@
+79 14 55 13

day5/example/soil-to-fertilizer

@@ -0,0 +1,3 @@
+0 15 37
+37 52 2
+39 0 15

day5/example/temperature-to-humidity

@@ -0,0 +1,2 @@
+0 69 1
+1 0 69

day5/example/water-to-light

@@ -0,0 +1,2 @@
+88 18 7
+18 25 70

main.go

@@ -3,11 +3,11 @@ package main
 import (
 	"log"
 
-	"sunshine.industries/aoc2023/day4"
+	"sunshine.industries/aoc2023/day5"
 )
 
 func main() {
 	log.Print("> starting run:")
-	result := day4.Run()
+	result := day5.Run()
 	log.Printf("day4 result: %d\n****\n", result)
 }